Rename fields in CourseTaskLog, including a task_key column for indexing.  Use 'rescore' instead of 'regrade'.  Clean up task submission.

Refactor tracking and xqueue initialization to no longer require a request.  Get tracking logs to work.  Add transaction annotations.

Make sure to read only once from result objects when getting result status,
so that values are consistent.

Add CourseTaskLog, and make calls to regrading.

Add regrading implementation, and hack the marshalling of request.

Fixes JIRA LMS-203

allow for an optional throw_on_not_found on contentstore().find() so we can clean up caller logic in the tests

add new collection configuration to support a 'trashcan' for assets. Update class factory to allow callers to specify if they want the default set of assets or the trashcan

Moved the definition of autoplay attribute to videoalpha_module.py file. Changed double negative if statement for autoplay check to simple if.

Copied autoplay attribute from video xmoudle to videoalpha. Now students will have the video autoplaying, and in Studio it will be pause by default.

If Video Alpha is playing a YouTube video in Firefox in HTML5 mode, then when switching to speed 1.0 it will simply reload the iframe, instead of using the built-in method to change the speed. The fixes the bug temporarily, while the YouTube team fixes the bug internally in the API. Commented additions to fix YouTube firefox speed 1.0 switch bug.

Especially the var[0].isdigit() one.

stores_state is now only used in a single test, in conjunction with
has_score. In practice, it's never the case that stores_state is false
when has_score is true, so we can delete stores_state entirely, and just
use has_score for the grading test.

-Clean up `SUFFIXES` from interspersed commented-out suffixes
-Remove unused `LOG`
-Remove unused method `raiseself` of UndefinedVariable and its usage